Oven-thermometer



' (No Model) beets-sheet 1.

- D. G. COOPER. OVEN THERMOMETER.

No. 447,129. Patented Feb. 24, 1891.

I I 1 w ,F WIIIIIH 11 1 I \rmm (No Model.) A 2 Sheets-Sheet 2.

D. G. COOPER. OVEN THEEMOMETER.

Paten-tedvFeb.'24,1891.

W: mums PETERS 1:11.. maro-umm, wnsnmcn'cu, 0.1:.

ITED STATES PATENT TL -I QJ DAVID G. COOPER, OF PEQUABUOK, CONNECTICUT.

OVEN-THERMOMETER.

SPECIFICATION forming part of Letters Patent No. 447,129, dated February24, 1891.

' Application filed January 21, 1890. Serial No. 337,581. (No model.)

To all whom it may concern:

Be it known that I, DAVID G. COOPER, a

V citizen of the United States, residing atPequabuck, in the county ofLitchfield and State of Connecticut, have invented certain new anduseful Improvements in Oven-Thermometers, of which the following is aspecification.

My invention relates to improvements in oven-thermometers and theprincipal objects of my improvement are simplicity and economy ofconstruction and general efficiency in use.

In the accompanying drawings, Figure l is a front elevation of mythermometer, together with a portion of an oven-door, to which it isapplied. Fig. 2 is a plan or edge view of my thermometer with ahorizontal section of the portion of the oven-door and thethermometer-hood on the line as a: of Fig. 1. Fig. 3 is a frontelevation of my thermometer with the bezel-ring and dialremoved. Fig. 4is a horizontal section of my thermometer on line a: w of Fig. 1, thescrews and indexshaft being shown in elevation. Fig. 5 is a verticalsection of the same on line y y of Fig. 4, the index-shaft being shownin elevation. Fig. 6 is a rear elevation of the same with the cap andmovement-plate removed. Fig. 7 is a detached view showing the broad sideof the movement-plate. Fig. 8 is a detached view showing the broadsideof the main plate. Fig. 9 is an edge View of the movement case or rim.Fig. 10 is a like view of the dial case or rim, and Fig. 11 is adetached view showing the broad side of the rack.

My thermometer is principally designed for use upon the ovens of kitchenstoves and ranges; but it is applicable for use upon any oven or hot-airchamber when it is desirable to indicate the temperature thereof.

In constructing my thermometer I form a principal or main plate A, themiddle or body portion of which is substantially in circularform,withlaterally-projecting side lugs 11 11 on diametricallyoppositesides, which lugs are perforated to receive bolts for fastening thecomplete device in place. Said main plate is also provided with a seriesof elongatedopenings 12, arranged in a circle near the outer edge of theplate, which openings are designed to receive the lugs 13,-correrim.

sponding in number and position on the movement case or rim B, the samebeing secured by riveting or heading said lugs. This case or rim B isgrooved at its periphery, as shown at 14:, and its back is covered by athin metal cap 15, which fits upon said case or rim snugly, like abox-cover, the flange 'of the cap being of a width that will reach thegroove 14 and its edge is'turned into the groove slightly, as shown bestin Figs. 2 and 4, to firmly secure said cap upon the case or rim B.

The main plateAis provided with a second series of perforations 16 on asmaller circle to receive correspondingly-arranged lugs'17 on the edgeof the dial case or rim 0, which in like manner is secured by rivetingor heading said lugs. This dial-case is perforated at two or morepoints, as at 18, and receives upon its outside a bezel-ring D, which isturned over to form a bead at its front edge,

so that when slipped or crowded upon the dial-case and over thedial-glass 19, Figs. at and -5, it holds said glass firmly between thebead and the front edge of the dial case or edge of the bezel-ringwhenthe bezel-ring is in place, and portions of the bezel-ring areslightly indented and'pressed into said holes with any suitable punch orset, as shown in Figs. 2 and 5, to firmly hold the sash in place. Themain plate A is also provided with a pair of elongated openings 20 toreceive lugs 21 for securing the dial-bridge E in place, to which bridgethe dial F is secured by means of suitable rivets or screws The mainplate is also provided with a series of round perforations in its middleportion, of which three, as at 23, are to receive the pillars or posts2% of the movement-frame, and the other two 25 and 26 are to receivebushings 30, respectively, for the index-shaft 27 and the shaft 28 ofthe segmental rack 29. By the employment of said bushings I am enabledto make the main plate A also serve the function of one of the plates ofthe movementframe. The other movement-plate G is secured to the oppositeends of the pillars or posts 24, as shown,and isprovided with holes toconstitute bearings for the respective shafts 27 and 28. On themovement-case B, I swage or strike up a little boss or projection 31,which is raised to a point substan- The holes 18 are located at the reartially in the same plane as the rear edge of the movement ease or rim B,whereby a central support is formed for the cap 15, which prevents saidcap from being pressed against the ends of the shafts of the movement.The shaft 27 is provided within the movement case or rim with a pinion32,and in the dialcase in front of the dial with a pointer or index 33.The shaft 28 is provided with a segmental rack 29, the teeth of whichengage the pinion 32, and is provided at the end opposite the teeth withan adjustable arm 3-1.

To the inner walls of the movement case or rim B, I secure asemicircular bim etal strip 35, the free end of which is connected bymeans of the link 36 to the arm 34: of the segmental rack. A bimetalstrip, rack, and pinion in a thermometer of themselves are not new andare hereby disclaimed. In addition to these I provide the adjustable arm3i on the segmental rack, which I first form, substantially as shown inFig. 11, of a metal capable of being bent for the purpose of adjustingthe thermometer by bending said arm. \Vhile I prefer to employ saidadjustable arm as a matter of convenience, itis evident that other partsof my invention may be employed in connection with a rack having anon-adjustable point for the attachment of the link 36. Besides theadjustable arm, I add to this thermometer-movementthere-enforcingpiece37, placing the same between the sides of the ease and the end of thestrip that is secured thereto, said re-e'nforcing piece extending alongon the outer side of the bimetal strip for a short distance after itbegins to separate from the side of the case, thereby strengthening thestrip at its junction with the case, and yet leaving it with someelasticity at that point. During transportation or from any sudden jarthe strip is more liable to be injured by bending at its junction withthe case than at any other point, and by the employment of thisre-enforcing piece extending a little beyond the point of attachmentthis liability to injury is prevented. I secure this strip to the rim ofthe case by means of two rivets 38, and I place a second re-enforcingpiece 39 on the inner side of the strip and pass said rivets through theWhole. This seeondre-enforeing piece, or washer, as it may be termed,has the end that faces the body of the strip curved outwardly a little,as shown in Fig. 6, so as to allow free movement of the strip, andthereby do away with any angular bearingpoint of the strip. I arrangethe shaft 28 of the rack 29 centrally between two of the pillar-posts23, thereby making said pillar-posts serve as stops to limit themovement of the rack and prevent it from ever being turned in eitherdirection far enough to disengage its teeth from the pinion 3-4.

The dial may have any desired figuring or lettering upon it; but I havefound in practice that some arbitrary figures-ms, for instance, 1 to 12,as in a clock-dialis more readily understood than figures indicatingdegrees without any figure or figures to indicate the degreesFahrenheit, as in the ordinary thermometer. I also prefer to place thewords Warm, Low heat, Baking heat, and Very hot at the proper pointsupon the dial, and to so adjust the thermometer that the pointer standsat twelve oclock when there is no heat in the oven.

I have now described the thermo neter proper, and .will proceed todescribe'its at tachment to the oven and some special provisionstherefor. For its-best Workin g itshould be insulated from the oven, andin order to provide such insulation and insure that it shall be properlyplaced I arrange upon each of the lugs 11 11 a washer 40, of asbestus orother insulating or non-conducting material, and I secure the samethereto by means of clips 44, which are preferably T-shaped, and aresecured with the T-head upon one side, and the shank or middle portionextending through the hole in the washer and lug and then clenched uponthe opposite side, as shown in Figs. 3, l, and 6, so that the washerswill surely be in the proper place when the thermometer is attached tothe oven or stove door H. A hole is made in said doorlarge enough to letthe dial-case pass through it and proj ect a greater or less distanceupon the front of the door, and the thermometer secured by means ofbolts 41, passing through the door, and the lugs 11, either with orwithout the addition of other washers, although it is preferred to placeother washers thereon to bring the movement-case well into the oven,which.

additional washers, as at 42, may be of any suitable material, eithernon-conducting or otherwise.

\Vashers may be used in suitable thickness and number to make the frontof the dial-case project only a short distance through the door;

IIO

but if the room in the oven is wanted, or if for any reason it isdesired not to have the thermometer project so far into the even, asurrounding hood K may be placed on the front of the door, so as tosurround and inclose the dial-case, as shown in Figs. 1 and 2, therebyprotecting said case from the external air and at the same time givingan ornamental effect. This hood may be fastened on by the same boltswhich secure the thermometer.

I claim as my invention 1. In an oven-thermometer, the main plate A,having a series of perforations 12 and a series of perforations 16, withthe movement case or rim B on one side and the dial ease or rim 0 on theother, said cases having lugs received within said perforations forsecuring the cases to said plate, substantially as described, and forthe purpose specified.

2. In an oven-thermometer, the combination of the main plate A, formingone of the movement-plates, the dial-case on one side and themovement-case upon the other, with the posts or pillars 24, secureddirectly to said plate, and the plate G, secured to said posts, saidplate A having perforations and 26, with bushings for bearings of theshafts of the movement, substantially as described, and for the purposespecified.

3. In an oven-thermometer, the combination of the movement-frame and itscase or rim B, the plate G of said movement-frame, with the boss orprojection 31 formed thereon, and the cap 15, held out of contact withthe movement-shafts by said boss, substanlt iially as described, and forthe purpose speci- 4. In an oven-thermometer, the rack 29, provided withthe curved adjustable arm 34, substantially as described, and for thepurpose specified.

5. In an oven-thermometer the movements of which consist, essentially,of an actuatingstrip, a segmental rack and its shaft, and an index shaftand pinion, the combination of the two lower pillar-posts 24, the shaft28 for said rack, located between said pillar-posts 2i and the pinion32, said two posts serving as stops for limiting the movement of therack, substantially as described, and for the purpose specified.

6. In an oven-thermometer, the combination of the curved bimetalstrip,the movedescribed, and for the purpose specified.

S. In an oven-thermometer having fasten ing-lugs, the combination ofsaid lugs with the non-conducting washers and clips 44: for securingsaid non-conducting washers in place prior to attachment, substantiallyas:

described, and for the purpose specified.

9. The combination of an oven -thermometer having a circular dial-casefor projecting through the door to which it is attached, and thesurrounding ornamental and protecting hood K, adapted to be secured withthe same bolts by which the thermometer is secured in place,substantially as described, and for the purpose specified.

DAVID G. COOPER. Vitnesses:

JAMES SHEPARD, JOHN EDWARDS, Jr.

